In Vitro Toxicity Effects Study Of Polystyrene Microplastics And Multiple Environmental Pollutants In Single/Combination And Applications

Microplastics（MPs）are defined as plastic particles smaller than 5 mm.MPs are widely present in the environment,and the types of studies are mainly focused on investigation and sorption,but there are fewer investigations on microplastic toxicity.Biomarkers are commonly used in environmental pollution monitoring and have the advantages of rapidity and sensitivity,therefore,in this study,in vitro biomarker method was used to detect the biotoxic effects of microplastics and other typical environmental pollutants.The toxic effects of 12 types of contaminants,including metal ions,brominated flame retardants and pharmaceutical active compounds,on the activities of two biomarkers,7-ethoxy-isophenoxazolone deethylase（EROD）and glutathione sulfotransferase（GST）,were investigated in a single/combined mode.Also,the effects of microplastics and copper ions on DNA damage under single/combination to THP-1 cells was investigated using comet assay method.In addition,this job investigated the biotoxicity of water and sediment samples in Fujian area using in vitro biomarker method to provide new ideas for realizing biomarkers for environmental monitoring.The results showed that:（1）Under single exposure,microplastics had no significant effects on in vitro EROD activity,at the exposure of room temperature,only Cu²⁺（1 mg/L）of the three metal ions inhibited EROD activity at the highest concentration,and brominated flame retardants had no significant effect on enzyme activity,and among the pharmaceutical active compounds,except erythromycin（EM）,the remaining five drugs could greatly inhibit EROD activity.The metal ions and brominated flame retardants（except BDE-209）extremely inhibited EROD activity and the lowest effect concentration（LOEC）decreased after the above three types of pollutants were co-exposed with microplastics.The change patterns of pharmacologically active compounds are more complicated.（2）Under single exposure,microplastics had no significant effects on GST activity in vitro,but all other three contaminants notablely inhibited GST activity at lower concentrations,with metal ions and brominated flame retardants both having LOEC of 0.01μg/L,and the pharmacologically active compounds significantly inhibiting GST activity at 10μg/L.After compounding with microplastics,all three metal ions inhibited GST more strongly than single contamination,showing an increase in the highest inhibition rate.Similarly,situations existed for brominated flame retardants and pharmaceutically active compounds appears to be the same.（3）Using THP-1 cell line as a test model,the DNA damage of microplastic and Cu²⁺under single/combination was examined by comet assay,and the results showed that both 2μm（10、15、20、25 mg/m L）microplastic and Cu²⁺（50、100、500、1000、2500、5000μg/L）can caused DNA damage to THP-1 cells,and the DNA damage effect increased after co-exposure.In addition,the actual damage value was higher than the theoretical sum of single damage.（4）In vitro toxicity monitoring was applied to evaluate the sediments in Dongshan Bay water,Yundang Lake,Xinglin Bay,Jiulongjiang Estuary and Luoyuan Bay.The results showed that the quality of Dongshan seawater was good and did not cause great inhibition or induction of EROD activity.While sediment samples from the other four coastal areas significantly inhibited the EROD and GST activities.Comparing with the results of chemical analysis and the results of environmental investigations in the past years,the biomarker results had a function of ecological risk warning effect on some stations.